RBP4 and diabetes mellitus: With this AUC, RBP4 presented a greater discriminatory ability to diagnose DR compared with HbA1c (AUC 0.71; 95% CI: 0.63–0.78; P<0.001), Hs-CRP (AUC 0.65; 95% CI: 0.59–0.72; P<0.001), diabetes duration (AUC 0.62; 95% CI: 0.55–0.69; P<0.001), and HOMA-IR (AUC 0.73; 95% CI: 0.68–0.80; P=0.005).